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- YALE UNIVERSITY • SCHOOL OF FORESTRY 

BULLETIN No. 7 

A PROGRESS REPORT OF 
THE RESULTS SECURED IN TREATING 

PURE WHITE PINE STANDS 

ON EXPERIMENTAL PLOTS AT 
KEENE, NEW HAMPSHIRE 

BY 
RALPH C. HAWLEY 

Professor of Forestry, and Forester in Charge of the School Forests 





NEW HAVEN 

Yale University Press 

1922 



YALE UNIVERSITY • SCHOOL OF FORESTRY 

BULLETIN NO. 7 



YALE UNIVERSITY • SCHOOL OF FORESTRY 
BULLETIN No. - 



A PROGRESS REPORT OF 
THE RESULTS SECURED IN TREATING 

PURE WHITE PINE STANDS 

ON EXPERIMENTAL PLOTS AT 
KEENE, NEW HAMPSHIRE 



BY 
RALPH C. HAWLEY 

Professor of Forestry, and Forester in Charge of the School Forests 




NEW HAVEN 

Yale University Press 

1922 



^■^;t^- 



c:* 



CONTENTS 



Location of the Plots 
Character of the soil 



Page 

Purpose of the Report c 

5 

5 

The site quality 6 

Classification of the Plots lO 

The Thinning Experiments lO 

Description of the experiments lo 

Tables of statistical data compiled from the measurements 

taken on the thinned and unthinned plots 14-22 

Summary of results 22 

The Experiments in Reproducing White Pine under the 

Shelterwood Method 29 



A PROGRESS REPORT OF 
THE RESULTS SECURED IN TREATING 

PURE WHITE PINE STANDS 

ON EXPERIMENTAL PLOTS AT 
KEENE, NEW HAMPSHIRE 



PURPOSE OF THE REPORT 

IN October, 1905, nineteen permanent sample plots were established in 
the white pine type near Keene, New Hampshire, by the United States 
Forest Service in cooperation with the Faulkner and Colony Manufacturing 
Company on lands owned by the latter. The plots were remeasured in 1909 
and again in 191 5 by representatives of the United States Forest Service. 
After the 19 15 measurement the plots were turned over to the Yale School of 
Forestry. In September, 1920, the plots were remeasured for the third time, 
three additional plots were established and six of the original plots were dis- 
continued. Fifteen years have elapsed since the beginning of the experi- 
ments. While the experiments are only partly completed, information of value 
in reference to the management of white pine has been acquired. The pur- 
pose of this publication is to make the information available for foresters 
and landowners engaged in managing white pine lands. 

LOCATION OF THE PLOTS 

Keene, New Hampshire, is located in Cheshire County in the south- 
eastern part of the state, approximately 16 miles north of the Massachusetts 
state line and 13 miles east from the Connecticut River. It is an important 
New England center of the white pine box and woodworking industries. 
The area is within the New England white pine region. 

Character of the soil. — Within the New England white pine region at 
least two distinct classes of upland (or well-drained) sites can be dis- 
tinguished. One consists of the heavier, more fertile soils, the other com- 
prises the lighter, sandier, and more sterile soils. Pure stands of second 
growth white pine are found on both classes of site, principally on areas 
cleared for pasture or cultivation and later allowed to grow up to forest. 
Upon the heavier, more fertile soils the pine meets severe competition from 
many hardwoods, several of them faster growing in height and more shade 



PURE WHITE PINE STANDS 

enduring than the white pine. On the lighter, sandier soils fewer hardwoods 
compete with the pine, and those which do, offer a weaker competition 
against the white pine than do the same species on the more fertile soils. This 
difference in character of competition between the pine and hardwoods has 
important bearing upon the management of the white pine type. Treatment 
which may be successful upon one class of site will not necessarily be satis- 
factory upon the other. 

The Keene plots are located upon the river plain of the Ashuelot about 
50 feet above the level of the river. The soil is a fine, deep sand, droughty 
in summer. Although level and free from stones the land is considered rather 
light for agricultural use. 

The area may be considered as typical of the second class of upland sites, 
just described, upon which hardwood competition with pine is weak. 

Hence the information contained in this report is applicable primarily 
to this class of upland sites. It should apply to such sites where found 
throughout the New England white pine region. 

The site quality. — ^The site may be further classified as lying between 
Quality II and Quality III and closest to the latter. 

This statement is based on comparison of values secured in the unthinned 
plot, number 604, with corresponding values given in the best existing 
yield table for white pine.^ Table i shows the comparison. 

The average heights of dominant trees, total basal areas and volumes in 
cubic feet, computed for the years 1905, 1909, 191 5, and 1920 when the 
stand was successively 35, 39, 45, and 50 years of age, have been compared 
to corresponding values for Quality II and III sites taken from the yield 
table. 

Height was assumed to be the best criterion of site quality, hence this 
factor was used first in comparing plot 604 with the yield table. 

The results of this comparison show that in 1905, when 35 years of age, 
plot 604 had an average height four per cent above Quality II site values ; 
in 1909, at the age of 39 years, its height was less than one per cent above the 
Quality II values; in 191 5, when 45 years old, the height was midway 
between Quality II and III ; and in 1920, at the age of 50 years, the height 
was about three per cent above the Quality III site values in the yield table. 

If the figures are taken literally the plot has changed during the 1 5 year 
period from site II to site III. This anomalous situation must be due to 
discrepancies in the data. Since plot 604 has remained unthinned the 

^ White Pine under Forest Management, by E. H. Frothingham, Bull. 13, United 
States Department of Agriculture, pp. 21 to 23. 







Volume in cubic 






O 
O 


O 

o 








feet 






-*• 




•4- 






0^ ?" Basal area in 






T*- 


■^ 


Sv 






O H 






Ov 


o 


,K 






£ ;3 sq.feet 








N 


c 
2 






J D Average height 






CO 


o 


15 






< 5 of dominant 
^ rj /r<f^j- />/ feet 






00 


L/S 


^ 




■Sk 


Q J I 










«r 






►J o 

>• f-c r Volume in cubic 


o 

00 


O 


o 
o 


o 

O 


1 




in cubic feet on 
' pine yield tab. 


s: ^ ^ 

w S ^ Basal area in 

1 H :3 .^./../ 

'^ ^ <3 

^ >-< D Average height 

w g of dominant 

[-, > /"/v^/ in feet 




<5 


M3 


O^ 

N 


bo 

< 
<*- 

o 

c 
<u 




OS 

•4- 


O 
N 

d 


N 
N 

O 
00 


PTi 
N 

o 
4- 


1 
Q 

S 






•^ 


i^ 


UTv 


so 


«? 




11 


%^ ^ 










-o 




O =^ 










'H 


•^ 


<2 




Volume in cubic 


o 
o 


o 






D 

m 


w 


-^ :: 


CO 

w 


feet 


N 








C 




I areas, an 
gures from 


;5 H Basal area in 
o< Average height 


00 
N 

O 


N 
N 

LTV 






"3 
oa 

C 








of dominant 
trees in feet 










12 
o 




-r'S 












X 




■5 s 




^ 


so 


VO 


oo 


W 




of heigi 
corresp 


Actual volume in cubic feet 


N 

oo 


4- 


Os 

o 
4^ 


o^ 


i 




rison 
with 


Actual basal area in square 


00 
00 


00 
00 


N 


so 


<3 




feet 


so 




•sd 

00 


4- 

Os 




Q 




N- 1 


CI 






















1 




Average height of dominant 


r«-i 


u^ 


Tj- 


oo 


w 




Cj 


trees in feet 




6 






K 

a; 








l-r\ 


ON 


vrs 


o 


%i 






>3 


o 


o 


1-1 


N 


•^ 






» 


o\ 


OS 


0\ 


OS 


g 






"a 


« 


"" 


l-> 


p-« 






^ 


c3 


^ 


^ 


^ 


* 






V 




" 


"• 


"• 








^ 


Ui 


^ 


>• 


^ 








<^ 


>N 














^ 


vr\ 


OS 


ur\ 


o 










c<-> 


ro 


^ 


lo 





PURE WHITE PINE STANDS 

figures, upon which "average heights of dominant trees" are based, had to 
be secured from hypsometer measurements of standing trees. There may be 
small errors made in securing the average height of dominant trees under 
this method but hardly enough to affect the comparison. 

Basal area and volume as factors for measuring quality of site usually 
are considered less reliable than height, because the total basal area or 
volume depends upon the density of stocking as well as upon the quality of 
site. It is only in fully stocked stands or in those whose per cent of stocking, 
as compared to the fully stocked, is known that either basal area or volume 
can be employed to fix site quality. 

When once the quality of site is determined for a given plot the basal 
area may be used as an indicator of the degree to which the plot is fully 
stocked. 

Taking the height as the indicator of site class and basal area as indicator 
of degree of stocking the following result is secured when comparing plot 
604 with the yield table already used. In securing these figures interpola- 
tion has been made between printed values in the yield table. 



Plot 604 



Was at age 


Stocked 


in fer cent of a 


in years 


fully stocked stand 


35 




82 


39 




85 


45 




90 


50 




93 



In order to check with the yield table the volumes in cubic feet actually 
measured on the plot at the different ages should be only those proportions 
of the volumes in the yield table which the basal areas bear to the basal 
areas of a fully stocked stand. Compared in this way the actual volumes 
show only slight differences as indicated below from those in the yield table. 

THE ACTUAL CUBIC FOOT VOLUMES ON PLOT 604 



At age in 


Differ from the volumes in 


years 


the yield table by only 


35 


6 per cent 


39 


2 " " 


45 


2 " " 


50 


2 " " 



In conclusion, height, basal area, and volume as actually measured on 
plot 604 at intervals for the last fifteen years are in harmony with one 

8 



o , 

CO ■'^ 

O ^ 



o 









s; --Q 



h 



^ 



^ 



^ ^ 



^ 


VO 


.** 


O 


■** 


On 


<s 




^ 




^ 


v*^ 


« 


-^ 




•^ 


<-5 


»a 












C5^ 






^ 



Si 






"3 



Cq ^ 



^ 



^ 



^ 



53 ^ 



;|^ 






^ ^ T^ tJ- r}- 



\Q U^ lj~\ \0 



r^ VO O 00 >j-\ 

— r^ N 00 t^ 

r^ N r^ — OS 

ur\ ur\ vO vO '^^ 



VO vO vO 

o o - 



ON ON 

o o 



^ «- Ti- r<-, ly-^ 

VO r^ f^ •^ f^ 
Tj- "1 -^ -^ Th 



Tf- O O VO t^ 

Qs vO VO r<-i 00 

r^ t\ O OO 00 

r<^ r<-) -^ t-O ro 



VO -^ NO N L/~. 

N OO >-^ — On 

N On 00 Lr^ 00 

•» #N •^ •^ »* 

vO N "^ L/^ "^ 



t-^ ON '-^ 00 00 



o o o o 

NO NO NO VO 



o w ■ — ' »J 



p^ 



PURE WHITE PINE STANDS 

another and when one is secured from the yield table the others will be 
found to check closely. But, during the 15 year period the three sets of 
values run across the yield table from the Quality II to the Quality III 
columns. 

Judging then from the course of development of plot 604 over a 1 5 year 
period it would seem that the values in the yield table at different ages and 
on different qualities of site are not in complete harmony with the natural 
development of pine stands. 

CLASSIFICATION OF THE PLOTS 

The permanent sample plots are arranged as follows in two series: 
A series to show the results of thinnings ; consisting of main plots 
numbered 601, 602, 603, and 604 ranging in size from 0.25 to 0.5 acres and 
reproduction plots 601 -A, 602-A, and 604- A, each one square rod in area. 
A series to show the results of reproducing white pine under shelter- 
wood (the shelterwood method) consisting of main plots Nos. 605, 612, 
and 614, ranging in size from 0.25 acre to 0.5 acre and reproduction plots 
Nos. 606-610, 613, and 615-619, covering one square rod each. 

THE THINNING EXPERIMENTS 

Description of the experiments. — The purpose is to bring out the differ- 
ences in growth and development resulting from different methods of 
thinning as compared to unthinned stands. Four plots were established in 
1905 in the pure white pine type on a level, sandy area of uniform site 
quality and with fairly uniform density of stocking and silvicultural 
condition. The location of the plots with reference to each other is shown 
on the accompanying diagram. 

The relative condition of the four plots at the time of establishment may 
be judged from the data in Table 2. The small range between the plots 
in basal area and cubic contents is particularly significant as indicating 
their similarity. 

Table 3 indicates the treatment given the sample plots after their estab- 
lishment in 1905. It will be noted that plots 601 and 602 have been thinned 
in the same manner each time; the former with a moderately heavy (C 
grade) thinning and the latter with a light (B grade) thinning. A direct 
comparison is thus afforded between light and moderately heavy thin- 
nings. 

10 








Plato 66\ to 604 



^k 



II 









' 


'^ o 


IT ° 


if ° 




■^ o 








5 -S 


C 


2^ ON 


c^ ON 


ON On 




2^ 2^ 








^ *« 


Q 




















^ 


ON -13 
O (3 


On 'O 

o S 


On tJ 




On 13 
O C 








^ 




On rt 


ON '^ 


ON ^ 




On « 








>i 




















^ 
^ 






















i^ 


ly-\ 


lv-\ 




iy-\ 








^ *« 


5 


O 


O 


o 




O 










ON 


ON 


ON 




ON 








s^, 


1— • 


l-N 






l-H 








^ 


















"A 




















■*-» 




' 


















^ 




















^\ 








^ 60 ID 


>:- 60 <u 


>^ 60 


<U 












O 

N 


rt c -a 


w C -n 


rt c 


-TD 








-'^ 






.5 c b 


.S 'S s 


.S 'S 
















ON 


6 '-5 u 


-d C 60 

O '-2 M 




60 
U 








<? 






















■Vj 






















^ 




















• 


•^ 
























V 




t-r\ 


inary 
ning 
rade 


inary 
ning 
rade 


?> 60 

.3 c 




C 

.S 










ON 


-^ .5 "^ 

o S u 


-13 .C 60 
O ^ CQ 


-^ .S 

6^ 


60 

o 




< 

r 
















s 




tr" 








60 

a 


60 

C 


60 




o 










OS 




'5 






_K! 






V> 


»> 




O 

ON 


3 

o 

o 


o 
o 


o 
o 




O 

(J 






■^ 








Z 


iz; 


^ 










■a 






















^ 






















"^ 






















^ 






o 

On 


dinary 
nning 
grade 


dinary 
nning 

grade 


Thinning 
Borggreve's 


o 
-a 
















6 ^ ^ 


6 -s M 


6 












V, 






















o 


o 


O 




o 








f^ 


§ 


NO 


NO 


NO 




NO 





12 



PURE WHITE PINE STANDS 

Plot 603 received in 1905 a heavy selection thinning (Borggreve's 
method). A number of relatively poorly formed and large crowned domi- 
nant trees were removed. To partially cover the openings created by this 
cutting most of the intermediate and overtopped trees were left standing. 
Unfortunately the presence of these trees made the removal of the large 
dominant trees a difficult task. In the logging many of the unmarked lower 
class trees were destroyed. After the cutting gaps were left, where the large 
trees stood, which have not closed in the succeeding fifteen years. In 19 15 
it was decided that to continue thinning among the biggest, dominant trees 
(Borggreve's method) was unwise, since the portions of the plot from which 
dominant trees had been taken in 1905 still showed wide gaps in the crown 
cover, while other portions of the plot were too densely stocked. Many inter- 
mediate and overtopped trees were in poor condition. The method of thinning 
was therefore changed in 191 5. In that year and in 1920 plot 603 received 
C grade thinnings. 

A comparison can eventually be drawn between plots 601 and 603 to 
indicate the results of C grade thinnings when applied with and without a 
first thinning according to Borggreve's method. 

Plot 604 from which no trees have been cut serves as a basis for com- 
parison with the plots which have received thinnings. 

On all plots the slash resulting from each thinning, after close utilization 
of merchantable material, has been left on the ground to decay. 

Tables 4 to 12 inclusive show the results so far secured as indicated by 
the measurements in 1909, 191 5, and 1920. The numbers at the head of 
the columns progress consecutively through all these tables in order to make 
easy descriptive reference to any column. 

Results for the period 1905 to 1909 are less reliable than for the periods 
1910 to 1915 and 19 16 to 1920 and should be given small weight in 
drawing conclusions. The reason for this is that many unmarked trees 
were cut or destroyed by the lumbermen in making the thinnings in 1905 
without an adequate record being kept of such losses to the unmarked stand. 
For further explanation see page 23. 



13 



PURE WHITE PINE STANDS 

Tables'^ of statistical data compiled from the m,easurements taken on 
the thinned a?id unthinned -plots. 







'■ 















r 
















so 
















S -^ 


















N 


00 vo 


o 






1~^ 






O 


O f^ 


o 










N 


r<^ N 


MD 








O "^ 














N 














ON 














N^ 










4 






::! .1" 


00 


O O 


o 




s 


^o 






N 


^ >o 


o 










N 


t^ N 


^o 




•^ 














"Xj 














Si 






r bo 










SS 






i^ « 












5 




^ ':i 


CO 


N ^O 


rt- 




^ 


W*i '*^ 




N 


\J\ t^ 


00 




•^ 
S 




N 


r^ N 


NO 




« 


^ ir " 










■^ 


K ^ 










s 


%j p— 










<« 


■cv. 












• ^ 


5 


O 


O VO 


^ 










vo 




OO 
NO 




PQ « 














1 - 


Th 


^ ^ 


tJ- 




^ >. 


-1 O 




L^ OO 


O 

OO 




'S 














5v 














<lj 














^ 














<-) 






r ^ 


















N 


'^ 00 


00 




M 




) 


VO 




N 

OO 




^ 




c 










V. 




ON 










"^ 




1— < 










-Si 






•^ ^ 










g 






iC *^ 


00 


O N 


OO 




^ 


^^ 






t^ 


N r<-i 


N 








r-^ 


0\ O 


OO 








.'^^ 














^ 












k 














n 


N f-<-) 


rt- 






o 


o o 


o 






VO 


^O VO 


NO 






S; 











"Tables 4 to 12 were compiled from the original measurements by Mr. W. H. 
Meyer. 

14 



* 



s; 

s I 



^ 



^ 



b-. .^ 



'^ S II 



so 



^5 _ 

^ II 



- - r o 

'ii -5 O ft; 
ft< -S5 ON "a 









^ 2" 



OS 
O 

OS 



St 












^•5 

-Si 



^ 



rj- O ^ "^ 
OS 00 <-o 00 
OS u»~, t\ ■^ 

OS 00 OS OS 



O t1- N SO 

N \o OS OS 

N U^ L^ O 

•\ « •< *> 

so - Tj- "^ 

N N N N 



00 N O 

OS HN t(- 

'^ r^ OS 

O 4- o" 



N N N so 
N ur\ >-^ OS 
r^ OO <3 O 



^ O '^ SO 

Lr\ OO 00 OS 

-^ f^ r<1 O^ 

r^ rC ■<?• ^ 

«- « M N 



00 o '^ '^ 

00 vo u^ r<i 
tA 4 -" N 



OS urv N 

o" rC so" 

N „ — 



00 N O SO 

-« « SO OS 

r<-) ur\ ro O 

i^ <~?i " OS 



SO N O N 

SO OS N — 

r^ p-i so i-^ 

ro N Os "^s 



-^ ^ 


so 


tI- so N 


i- -^ 


N 


OO l^ — 


'^ s 


N 


OS CO ur- 


■^ -$ 


SO 


N ■+ L<- 



O O O O 

SO so SO SO 



15 







TABLE 


6. 




Mean 


and periodic annual growth per acre in 
in thinned and unthinned stands. 


board feet 




18 


19 


20 


21 




/ 


Growth 


in board feet 


N 




Mean annual^ 


, 


— Periodic annua 


I 




Plot 


through the 


1906 to 


1910 to 


1 9 16 to 


number 


•fear 1905 


1909 


1915 


1920 


60 1 


464 


388 


813 


713 


602 


371 


330 


657 


664 


603 


424 


435 


794 


646 


604 


443 


896 


523 


573 




* Age of stand for all plots was 


35 years in 1905. 





16 






^ 
s 
Q 



~5 



^ 









\o ■»>, 



l-r\ i-i 

O O r^ 



^ ^ ^ O 



■'^ <u ON 



'^ „ 



^ ::i 



« o 



o< 



■~ S; O 
0\ 



^0 



•^ 






ON 

o 



o 

ON 



^1 



^ 
^ 






1 bo 









U/-I \0 (^ '-" 
On r^ NO ON 
SO -"t- N — 



"- On N -< 
rj- -. m O 

u^ 1.^ u/^ L^ 



^ 00 N 

N N On 

NO 00 NO 

NO Tj- NO 



NO NO O 00 

N On ^ tJ- 
r--. t\ NO o 



- NO " 
OS t^ O 



m r<-) N 



On On On 
O L/-, O 



o 



O O O NO 

rn 00 -^ '-O 

VO ^ '^ "^ 

N N "" *^ 

^ •< "< " 

ro f<^ '^ "^ 









tJ- 


NO 


N 


tJ- 


00 


r^ 


Tt- 


On 


N 


C) 


*« 


»\ 




N 


r<-> 


r<-> 


Ti- 








ns 


NO 


NO 




1-4 


Lr\ 


r^ 


r^ 






r<1 r<^ tJ- r«-) 



« N <^ -^ 
GOOD 

NO NO NO NO 



S < 



'■B pa 

n ^ 

G s2 

.2 ^ 

-o ^ 



d ^ 



17 



TABLE 8. 

Mean annual and periodic annual growth per acre 
in cubic feet in thinned and unthinned stands. 

32 33 34 35 

^ Growth in cubic feet 



Ti/r 1 , Periodic annual . 

Mean annual f ^ 

Plot through the 1 906 to igio to igi6 to 

number year 1905 1909 J9'5 1920 




18 











r 


w 
V 


O 


^ 


OO so 














r^ 


SO 


00 r-~ 






N 








^^ 


ro 


J 


«' 4- 














O 


M-l 


On OS 




<-i 










^ 




M.4 


t^ 




^S 






o 












s; 






N 


S 










Q 






OS 


■S 










■»v> 






l-M 


<i 










^-5 










^. ^ 


o 


OO 


CO so 




^ 


-^ 












SO 

oo 


O (-- 

OO -4 




S 










«5 


— 


r<-i 


Os Os 




s 










>^ 


N-« 


HH 




• ^*k 


















■^ 


















■*^ 


















R 




.! 
















O 


C 


■Vj 


f' 


1° 


o 

00 


SO 
N 


d so' 










5 "- 


-, 


OS 


N 


OS 00 




■^ 






* !^ 


^ 










s 




J 


>^ OS 


^ 
♦^ 










s; 










<5 








cfs 


■-Si 




_fe 








00 
N 


O 

OO 


O N 




■<«» 


0\ 








^ 

^ 


r<s 


r<-) 


N sd 


W 






1 


s ^ 


aq 


i^ 


^y^ 


rt- OO 


J 


•*s» 




«4 






'"' 


'"' 


•^ 1— « 


PQ 






■e 


i. 










< 


^ 




■5 


s 










\> 




(. 






00 


SO 


SO 00 


is. 


CX3 








so 

oo' 




OS 00 












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21 



TABLE 12. 

Average height of the dominant trees in feet 
in thinned and unthinned stands. 



Plot 
number 



57 58 59 60 

-Average height of do7ni7ia?it trees in feet iti^- 

1905 1909 i9'5 1920 



601 


46 


50 


54-7 


59-7 


602 


45.8 


49-7 


54-7 


60.2 


603 


46 


48.3 


53 


57-7 


604 


46-3 


50.5 


53-4 


55.8 



* Secured by averaging the heights, taken from height curves 
for each diameter, of all the dominant trees. The height curves 
used were constructed partly from measurements of the total 
heights of trees cut on the plots in thinnings, but principally from 
fiypsometer measurements of trees standing on the plots. 



Summary of results. — The experiments must continue one to two decades 
longer before final conclusions can be drawn. Careful study of the figures in 
these tables should indicate the general effects of the thinnings. Tentative 
conclusions based on the data now on hand are presented in the following 
paragraphs. 



PURE WHITE PINE STANDS 

1 . The thimiings have reduced the number of trees per acre by percentages 
of the original numbers ranging from 67 to yy. During the 15 year period 
from 1905 to 1920 the number of trees per acre on the plot thinned C grade 
has dropped 74 per cent ; on the plot thinned B grade 6y per cent ; on the plot 
first thinned according to Borggreve's method yy per cent. The decrease 
on the unthinned plot due solely to natural causes amounts to only 28 per 
cent. 

Starting with 778 to 1,032 trees per acre in 1905 the thinned plots (601, 
602, and 603) now contain 202 to 308 trees per acre. The number of trees 
on the check plot (604) has been reduced by natural causes from 828 to 600. 
See Table 4. 

A comparison of columns 2 and 3 for plots 601, 602, and 603 would 
seem to indicate a large decrease from natural causes between 1905 and 
1909. Most of this decrease is accounted for by injuries to unmarked trees 
caused by the lumbermen in making the 1905 thinning. The figures in 
column 2 were compiled before the thinning from tally of the trees to be 
left rather than from an actual count of the trees left standing by the lumber- 
men. Many small trees were destroyed. 

2. The reduction in number of trees per acre has concentrated growth on 
fewer stems of larger average diameter and volume. See Tables 4, 10, 
and II. 

This is especially noticeable as a result of the C grade thinnings on plot 
601. To illustrate the point the respective values in columns 43, 49, 50, and 
56 for plots 601 and 604 are presented side by side. 

Plot 
Column 601 604 

43 Diameter of average tree in inches in 1905 

before thinning 6.1 6.0 

49 Diameter of average tree in inches in 1920 

after thinning 9.7 y.y 

Increase in diameter of average tree in 

inches during the 15 year period 3.6 1.7 

50 Average volume per tree in board feet in 

1905 before thinning 20.9 18.7 

56 Average volume per tree in board feet in 

1920 after thinning 77.8 41.8 

Increase in volume per tree in board feet 

during the 15 year period 56.9 23.1 

23 



PURE WHITE PINE STANDS 

The advantage is obvious. Fewer but bigger trees on the area tend to 
lower logging costs and permit the manufacture of larger sized and often 
better quality material. 

3. Height growth has been stimulated as a result of the thinnings. See 
Table 12. 

Starting in 1905 with approximately the same average height of dominant 
trees (column 57), the three thinned plots now have higher values than the 
check plot (column 60). 

The C and B grades of thinning (represented by plots 601 and 602) as 
yet show little variation in height growth, but are both ahead of the 
Borggreve thinning (plot 603). This is brought out in the following table: 



Table 13. 

Showing the effect of thinning upon height growth. 



-Average height of dominant trees- 



Height growth for period 1905-20 
in feet in percentages 

( Co/timn 57) ( Column 60) based on growth on 

Plot in 1905 in igzo check plot taJien 

number feet feet as 100 



601 46 59.7 13.7 144 

602 45-8 60.2 14.4 152 

603 46 57.7 II. 7 123 

604 46.3 55.8 9.5 100 



These figures indicate that height growth may be influenced by the 
silvicultural treatment of the stand. As a consequence, within the same site 
class different standards of height growth may have to be recognized. 

4. The actual amounts removed in each of the thinnings are show?i for 
each plot in board feet, cubic feet, afid on a percentage basis i?i Table 14. 

It will be seen that the plot thinned C grade (plot 601) and the one 
thinned in 1905 according to Borggreve's method (plot 603) and sub- 
sequently C grade, are close together in the total amounts removed ; though 
differing as to the percentages taken out in the individual thinnings. 

The 1905 thinning on plots 601 and 603 furnishes a good illustration of 
the difference between the C grade and Borggreve style of thinning. 

24 







1 ^ -S 

1 2^^-? s^ 


Cubic feet 


N 

NO 


00 N 

N ON 
00 NO 




^ 

^ 


Co 

mo tin 
move 
inn in 






^ NO 

— N 




•S 


•^ ^ ^~S 




00 


N 




S 
s 

•*** 

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1 -^5 ^^ 


Board feet 


ON 

0" 






■Kk 


Cj 






■^ 


"* 










Percentage 








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of total 


LTN 


l^ ^ 










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volume 








g 






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Amt. per 




00 


-f N 








c 


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NO 



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2.; 



PURE WHITE PINE STANDS 

The former removed 15 per cent of the board foot contents of the stand 
or 20 per cent of the cubic contents, while the Borggreve cutting took out 
35 per cent of the board foot volume but only 25 per cent of the cubic 
contents. The large percentage of the board foot volume cut is due to the 
removal of the largest trees which yielded a relatively high content in board 
feet as contrasted to cubic feet, whereas many of the smaller trees cut in 
the C grade thinning gave no yield at all in board feet. 

The B grade thinnings (plot 602) produced approximately half the 
volume of the other cuttings. 

5. The basal area fer acre is considered one of the best indicators of the 
character of the thinning. Ultimately a standard basal area per acre can be 
established for each degree of thinning. After and as a result of each thin- 
ning the basal area fer acre would be reduced to this standard. 

So far in this experiment no special effort has been made to bring the 
basal areas to any fixed standard. The basis for selection of the trees has 
been the crown relations and relative thrift of the individual trees. Inspec- 
tion of Table 9, particularly columns 40 and 42, indicates that after each 
of the last two thinnings the basal area of plot 601 (thinned C grade) has 
been brought down to approximately 100 square feet, while that of plot 
602 (thinned B grade) has been reduced to 125 square feet. 

In future thinnings on the plots these standards will be used. 

A record of the changes in basal area per acre since 1905 is given in 
Table 9. The discrepancies between corresponding values in columns 37 
and 38 are due to the same cause explained under Conclusion i, page 23. 

6. The annual growth fer acre exfressed either in board feet or cubic 
feet has been increased as a result of the thinnings. Plots 601, 602, and 603, 
as contrasted to plot 604 indicate this. See Tables 6 and 8. 

Results during the first four years after the experiment was started 
(1906 to 1909) contradict the above statement. See Columns 19 and 33. 
There may be two reasons for this. First, it may be possible that the bene- 
ficial effect of thinning is not always apparent for a few seasons in a stand 
previously closed. Second and most important in this instance, the large 
decrease in number of trees on plots 601, 602, and 603 between 1905 and 
1909, resulting from injuries to unmarked trees caused by the lumbermen 
in making the 1905 thinning, greatly reduces or in the case of growth in 
cubic feet on plot 602 (column 33) completely offsets the growth during 
the period 1906 to 1909. 

The periods i9ioto 1915 and 1916 to 1920 each show large increases in 

26 ' 



PURE WHITE PINE STANDS 

rate of growth on the thinned plots in both board and cubic feet. (See 
columns 20, 21, 34, and 35.) As is well recognized measurement in cubic 
feet affords a better expression of the relative wood producing power of 
the different stands than does the board foot unit. Consequently the values 
in columns 34 and 35 are particularly impressive, as indicating the effect 
of thinning on rate of growth. 

The slackening of growth in the unthinned plot (604) is striking as 
contrasted to the increase in plots 601, 602, and 603. 

7. WiiA a wood capital smaller tha?i in the unthinned stand, a thinned 
plot gives a higher rate of increase on the invested capital. 

It was shown under the preceding caption that the amount of material 
actually produced per acre per year was increased. Since the thinnings tend 
to reduce the total amount of wood capital remaining in the stand at any 
given age as contrasted to the unthinned stand, it follows that the rate of 
increase on invested wood capital should in theory be higher in thinned 
stands. 

This theory is borne out by the results of the experiment as shown in 
Table 15. 



TABLE 15. 

Showing the per cent of increase on invested wood capital 
in thinned and unthinned stands. 



Per cent of increase on wood capital present at 
beginning of period 

f 19 10 to \<)\ 5 ^ f 1 916 to 1920 



Plot Treatment Capital and increase reckoned in terms of 

number Board feet Cubic feet Board feet Cubic feet 



601 Thinned 32 24 26 25 

602 " 29 26 23 20 

603 " 42 20 29 25 

604 Unthinned 16 8 13 6 



Table 15 has been compiled from the figures in Tables 5 and 7. The 
period 1906 to 1909 was not considered because of the inaccuracy of the 

27 



PURE WHITE PINE STANDS 

data relating to the thinned plots after the 1905 thinning. For further 
explanation see page 23. 

The per cent of increase on invested wood capital is from two to four 
times greater in thinned as compared to unthinned stands. The use of 
thinnings thus affords not only an opportunity for reduction of the capital 
invested in the timber, but at the same time increases the amount of growth 
and its per cent in relation to wood capital. 

8. The decrease in wood capital resulting from thinnings would be of 
importance in lessening taxable values. If the volumes in board feet on the 
unthinned plot at any given time are taken as 100, then the volumes on the 
thinned plots at the same time are in the following ratio. (Computed from 
data in Table 5.) 

Volumes expressed as a proportion of the volume of 
the utithinned plot assumed as 1 00 

After thinning in 191 5 After thinning in 1920 
61 63 

65 67 

50 54 

100 100 

Thus the wood capital invested in the thinned stand ranges from 50 to 
67 per cent of that in the unthinned stand and ought to carry a correspond- 
ingly lower valuation. 

9. The comparatively early financial return secured from sale of material 
removed in thinnings has a most favorable effect upon reducing the cost of 
growing a crop of timber as compared to the imtlmmed stand. This relation 
is too well understood to require further elaboration here. 

10. The thinned plots are in more vigorous and healthier condition than 
the unthinned plot. This is evidenced by the relatively large number 
of dead and dying trees in the various plots. Very few dead or dying trees 
are found in the thinned plots and nearly all the standing trees have op- 
portunity to expand their crowns. In the unthinned plot the large number of 
living trees prevents even the best dominant trees in the stand from securing 
adequate room for crown expansion. 

1 1 . Pine reproduction, mixed with some hardwood becomes permanently 
established^ as a result of heavy thinnings. In 1905 when the plots were first 
established and for a number of years thereafter no figures were taken as 
respects reproduction. Recently such records have been started, but the 

28 



Plot 

7 iJ '977 nfif 


Treatment 


601 


Thinned 


602 


€< 


603 


<< 


604 


Unthinned 



PURE WHITE PINE STANDS 

results so far secured do not warrant more than the statement given above. 
Reproduction starting too early in a rotation may readily become a nui- 
sance and be something to prevent rather than to encourage. How heavy 
thinnings can be used and still keep out reproduction remains yet to be 
determined. 

12. Weighing all factors the C grade thinning is considered superior to 
the B grade or Borggreve thinning. An inspection of the three thinned plots 
is of value in reaching this conclusion. The appearance of the stand, and the 
character and spacing of the individual trees points to the relative desira- 
bility of the C grade thinning. 

THE EXPERIMENTS IN REPRODUCING WHITE PINE 
UNDER THE SHELTERWOOD METHOD 

As stated on page lo three main plots and eleven reproduction plots are 
included in the series. These may be further subdivided into three groups 
consisting of : 

a. Main plot 605 and reproduction plots 606, 607, 608, 609, and 610, 
illustrating the final stages of the shelterwood method. 

b. Main plots 612 and 614 and reproduction plots 613 and 615 illus- 
trating the early stages of the shelterwood method. 

c. Reproduction plots 616, 617, 618, and 619 established to show repro- 
duction following shelterwood cuttings, but about which insufficient data 
were secured at time of establishment to make the plots instructive. 

This report will deal primarily with Group a. 

Plot 605 of one-half acre in size was established in 1905 in a stand of 
close-grown pine, which had been lightly thinned in 1900 by the Faulkner 
and Colony Manufacturing Company, and so heavily thinned by the same 
company in 1904, as to leave the crowns of the trees barely touching or in 
the widest gaps 10 feet apart. Following the cuttings an abundant repro- 
duction started under the shelter of the remaining timber. Enough survived 
the final cuttings to fully stock the area. 

The plot was remeasured in 1909. In the winter of 191 2-1 3 the stand 
was cut clear. 

At the time of the first thinning in 1900 the age of the stand was 48 years. 

No detailed reports are available to show what was removed at each 
cutting, further than to indicate that the shelterwood method of repro- 
duction was employed. 

To trace the development of the reproduction resulting from these cut- 

29 





— 










-^ 


^ 























--. 


-5! .S 






















...^ 


























^ ■*<' 
























-^ ■-. 












-S 










v^ 
























S; 


ON s; ^ 












S 










Si 


« Si >^ 












ft; 










«5 












-^ 






















o 












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s; *^ 






















S 


SI 










g 




'■ r r 


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N 


ro NO 




NO 
00 


00 


o 

OO 
NO 




5v 




rri 




















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on following 
White pine 


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NO o 


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00 












o 

On 


r-^ 


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On 


o 
























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^ '5! 

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o 

ON 


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NO N 


o 


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ON 


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N 




§ 




















i./^ 






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^ 


















<2l 




s; — 
Si O 




















Co 






f^ 


Tt- 


00 


t~^ 00 


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00 


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00 ^ 




00 


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^ ^ 




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30 











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Cherry 

Hemlo 

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Apple 


<i 


6 












c 


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<-> 


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SO SO SO SO SO 




(^ ^^ 





31 



PURE WHITE PINE STANDS 

tings plots 606, 607, 608, 609, and 610 were laid off on or close to plot 605. 

The figures secured from these plots are presented in Table 16. 

White pine seedlings at the rate of 30,880 per acre were on the ground 
when the plot was established in 1905. These seedlings came in after the 
first thinning made in 1910 and originated from the heavy seed crop of 1904. 

In 1920 of these seedlings 7,200 per acre were still alive and together 
with 480 pine seedlings which started from seed crops subsequent to 1904, 
formed dense thickets of reproduction averaging 7 to 9 feet in height with 
some individuals as high as 15 feet. 

The causes which resulted in this large decrease in number of seedlings 
during the fifteen years from 1905 to 1920 can only be surmised, as detailed 
records of the seedlings which died were not kept in the early stages of the 
experiments. It seems likely that the beetle Hylobius^ Pales, known to be in 
the region, was instrumental in reducing the number of seedlings. 

A small amount of hardwood reproduction came in with the pine. In 1905 
other reproduction than pine totaled 416 per acre. In 1920, 352 hardwoods 
(including a few hemlock) per acre, principally birch and cherry, were 
present. 

At the time of each remeasurement the hardwoods which were overtop- 
ping pine were cut back to the ground. Very little of this work was needed. 
Now the pine is free. Hardwood competition with pine has not been a serious 
factor on these plots. 

The small amount of hardwood reproduction and its inability to com- 
pete strongly with the pine is attributed to the dry, sandy nature of the site. 

The pine tops remaining after the various cuttings were left on the 
ground as they chanced to fall. Utilization was close and the slash con- 
sisted mainly of the pine branches. The effect of this slash in controlling 
the local distribution of pine reproduction is marked. A comparison in 
Table 16 of plots 608 and 609 will bring out this point. 

Plot 608 represented areas having in 1905 the maximum amount of slash. 
Plot 609 represented areas having in 1905 the minimum amount of slash 
cover. This condition is reflected in the pine reproduction on the two plots. 
Plot 609 had the maximum reproduction of pine, 556 seedlings per square 
rod, while plot 608 contained only 48 seedlings per square rod. 

The following conclusions appear justified from the results secured on 
plot 605 and its accompanying reproduction plots. 

^The Life History and. Control of the Pales Weevil (Hylobius Pales) by H. B. 
Peirson. Harvard Forest, Bulletin No. 3, Petersham, 1921. 

32 



PURE WHITE PINE STANDS 

1 . Pine reproduction can be successfully obtained by cuttings 
under the shelterwood method. 

2. Hardwood re-production starts in smaller amounts than 
pine reproduction but will overtop a portion of the pine seed- 
lings. One or two cleanings to free the pine may be necessary, but 
should not prove so expensive as on more moist and heavier soils. 

3. The slash left after thinnings in white pine stands is not 
abundant enough to prevent reproduction stocking the area, but 
may lie thick enough over small patches to greatly reduce the 
amount of reproduction on such spots. 



Printed by the Yale University Press at the 
Earl Trumbull Williams Memorial.. 



